Organic matter removal performance, pathway and microbial community succession during the construction of high-ammonia anaerobic biosystems treating anaerobic digestate food waste effluent.

Abstract

This study aimed to establish anaerobic biosystems which could tolerate high ammonia, and investigate the microbial community structure in these reactors. High-ammonia anaerobic biosystems that could tolerate 3600mgL-1 total ammonia nitrogen (TAN) and 1000mgL-1 free ammonia nitrogen (FAN) were successfully established. The removal efficiencies of COD and total volatile fatty acids (TVFAs) in R1 with dewatered sludge as inoculum were 68.8% and 69.2%, respectively. The maximum methane production rate reached 71.7±1.0mL CH4 L-1 d-1 at a TAN concentration of 3600mgL-1. The three-dimension excitation-emission matrix analysis indicated that both easily degradable organics and refractory organics were removed from ADFE in R1 and R2. Functional microorganisms which could bear high ammonia were gradually enriched as TAN stress was elevated. Lysinibacillus, Coprothermobacter and Sporosarcina dominated the final bacterial community. Archaeal community transformed to hydrogenotrophic methanogen. The synergy of Coprothermobacter and Methanothermobacter undertook the organic matter degradation, and was enhanced by increasing TAN stress. This study offers new insights into anaerobic bioremediation of ammonia-rich wastewater.